Classifications

• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
  • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
  • G03F7/004—Photosensitive materials
  • G03F7/0046—Photosensitive materials with perfluoro compounds, e.g. for dry lithography
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F218/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an acyloxy radical of a saturated carboxylic acid, of carbonic acid or of a haloformic acid
  • C08F218/02—Esters of monocarboxylic acids
  • C08F218/04—Vinyl esters
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F8/00—Chemical modification by after-treatment
  • C08F8/12—Hydrolysis
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F8/00—Chemical modification by after-treatment
  • C08F8/44—Preparation of metal salts or ammonium salts
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F2810/00—Chemical modification of a polymer
  • C08F2810/50—Chemical modification of a polymer wherein the polymer is a copolymer and the modification is taking place only on one or more of the monomers present in minority

Definitions

• the invention relates to fluorine-containing copolymers containing, as monomer units, vinyl esters which, if appropriate, have been partly or completely saponified to give vinyl alcohol units, fluorine-containing, ethylenically unsaturated compounds, if appropriate ethylenically unsaturated monocarboxylic and/or dicarboxylic acids and, if appropriate, further copolymerizable compounds, the fluorine-containing monomer units in the copolymers containing, as side chains, fluorocarbon groups composed of at least 2 adjacent carbon atoms possessing F--C bonds, a process for the preparation of the copolymers and their use in various fields of application.
• the copolymerization of trifluorochloroethylene with vinyl acetate and the subsequent hydrolysis of the copolymer to give the corresponding alcohols are also described in British Pat. No. 596,943.
• the products obtained can be vulcanized.
• the copolymerization of 1-chloro-2,2-difluoroethylene with vinyl acetate is known from U.S. Pat. No. 2,891,934.
• the saponification of the copolymers to give modified polyvinyl alcohols is not mentioned.
• the copolymers are used for coatings, coats of lacquer, adhesives and films.
• thermo-reversible gel The preparation of a thermo-reversible gel is described in U.S. Pat. No. 2,499,097. It is obtained by copolymerizing vinyl fluoride with vinyl acetate and saponifying the copolymer. It is prepared in the form of a dispersion.
• copolymerization of vinyl acetate with tetrafluoroethylene at 50° C. is described in European Polymer Journal 3 (1967), No. 1, pages 5-12.
• the copolymers can be converted into the corresponding fluorine-containing copolymeric polyvinyl alcohols by alkaline hydrolysis.
• These products can contain up to approx. 20% by weight of fluorine, which is attached directly to the carbon atoms forming the main chains of the polymer molecules.
• Photosensitive fluorine-containing polymers are known from European Published Application No. 40,841; these are employed, in particular, for the production of offset printing plates and contain comonomer units having photosensitive groups.
• Copolymers formed from vinyl esters, ethylene and fluoroalkyl acrylates are known from European Published Application No. 86,406 and from Japanese Patent Application No. 81 0 1184.
• the copolymers are obtained in the form of a dispersion. It is not mentioned whether it is possible to saponify them to give modified polyvinyl alcohols.
• the present invention was therefore based on the object of making available polymers which have improved properties, which can be used in a versatile manner and which do not have the disadvantages of the known fluorine-containing copolymers mentioned above. It was regarded as a further object, in particular, to find copolymers which can be saponified to give copolymeric, modified polyvinyl alcohols having an improved dispersibility.
• the proportion of fluorine-containing comonomers according to the invention is preferably 0.05 to 60% by weight, relative to the total amount of monomers employed.
• the invention relates, therefore, to fluorine-containing copolymers prepared by the free radical-initiated copolymerization of ethylenically unsaturated, copolymerizable monomers and containing, as monomer units, vinyl esters, fluorine-containing, ethylenically unsaturated monomers, if appropriate ethylenically unsaturated monocarboxylic and/or dicarboxylic acids and, if appropriate, further monomers, the vinyl ester units being, if appropriate, partly or completely saponified to give vinyl alcohol units, wherein the fluorine-containing monomer units in the copolymers contain, as side chains, fluorocarbon groups composed of at least 2 adjacent carbon atoms having F--C bonds.
• fluorine-containing monomer units in the fluorine-containing copolymers according to the invention preferrred monomer units are those which correspond to formula I. ##STR1## in which R denotes H, --CH 3 or --CF 3 ,
• A denotes --CH 2 --, --O--, --CH 2 --O--(CH 2 ) m -- or ##STR2## in which R 2 and R 3 , which can be identical or different, represent H, (C 1 -C 4 )-alkyl, --CF 3 or R 1 ,
• n denotes 0-1
• m denotes 0-2
• R 1 denotes --C p F 2p+1 , --C p F 2p X, --C p F 2p-1 XH, which can be linear or branched, p denotes 2-20, preferably 6-12, and X denotes halogen.
• vinyl acetate is preferred amongst the vinyl esters in the fluorine-containing copolymers according to the invention.
• R 5 denotes H, --CH 3 or --COOH, it being possible for R 4 and R 5 to be identical or different,
• r denotes 0-5
• R 6 denotes H, NH 4 , Na, K or Li
• preferred copolymers are those in which the degree of saponification of their vinyl ester units to give vinyl alcohol units is 40 to 100 mole %, preferably 60-90 mole % and particularly 70 to 98 mole %.
• the invention also relates to a process for the preparation of the fluorine-containing copolymers according to the invention, described above, by free radicalinitiated copolymerization of copolymerizable vinyl esters with fluorine-containing, ethylenically unsaturated monomers, if appropriate ethylenically unsaturated monocarboxylic and/or dicarboxylic acids and, if appropriate, further monomers, and, if appropriate, by subsequent partial or complete saponification of the vinyl ester units to give vinyl alcohol units, which comprises employing for the copolymerization preferably 0.05 to 60% by weight, relative to the total amount of monomers employed, of fluorine-containing monomers in which the copolymerizable ethylene group is substituted by radicals containing fluorocarbon groups, the fluorocarbon groups being composed of at least 2 adjacent carbon atoms having F--C bonds.
• the copolymerization according to the invention is preferbly carried out in the mass and/or in solution.
• the partial or complete hydrolysis of the vinyl ester units to give vinyl alcohol units which is to be carried out, if appropriate, in the fluorine-containing copolymers is preferably effected by alkali-catalyzed alcholysis in accordance with known methods.
• Vinyl esters which are particularly suitable for use are, especially, the vinyl esters of saturated aliphatic carboxylic acids having 1-18, in particular 2-12, carbon atoms, such as, for example, vinyl formate, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl laurate or vinyl stearate. They can be employed individually or as a mixture with one another. It is preferable to use vinyl acetate.
• Examples of comonomers corresponding to the structural unit of the formula (I) are perfluorohexylethylene, perfluorooctylethylene, perfluoropropyl vinyl ether, allyl tetrafluoroethyl ether, allyl hexafluoropropyl ether or hexafluoroisobutene.
• the compounds belonging to the series of the perfluorinated ⁇ -olefins can also be employed as a mixture with one another.
• the perfluorocarbon part of the fluorine-containing comonomers must extend over at least two adjacent carbon atoms.
• Copolymers according to the invention are obtained, for example, by copolymerizing the fluorine-containing monomers with vinyl esters of saturated aliphatic carboxylic acids in the mass or in emulsion or in suspension or preferably in solution, using conventional initiators which are suitable for free radical polymerization.
• the reaction can be carried out by a batch process or a metering-in process.
• 0.05-20% by weight, relative to the total amount of monomers, of the fluorine-containing comonomer are dissolved in the vinyl ester, together with the free radical initiator, and the mixture is introduced into a reaction flask and polymerized at 60°-80° C. for 5-10 hours.
• An organic solvent can be added, if appropriate in several portions, during the polymerization.
• polymerization initiators which can be employed are organic peroxides, such as benzoyl peroxide, t.-butyl hydroperoxide, cumene hydroperoxide or dibenzoyl peroxide, azo compounds, such as azodiisobutyronitrile, and per-esters, such as t.-butyl per-2-ethylhexanoate, in an amount of 0.005-0.3% by weight, preferably 0.05-0.25% by weight, relative to the vinyl ester.
• organic peroxides such as benzoyl peroxide, t.-butyl hydroperoxide, cumene hydroperoxide or dibenzoyl peroxide
• azo compounds such as azodiisobutyronitrile
• per-esters such as t.-butyl per-2-ethylhexanoate
• Organic solvents which can be added to the reaction solution, in an amount of 10-60% by weight, relative to the vinyl ester, are primary, secondary or tertiary aliphatic alcohols, such as, for example, methanol, ethanol or isopropanol, preferably isopropanol and methanol and particularly preferentially methanol.
• Esters such as methyl acetate, are also suitable solvents.
• the copolymers according to the invention After the removal of the organic solvent, the copolymers according to the invention, which have been prepared in this manner and are present in an alcoholic solution, can be obtained in a solid form, preferably as granules, by known drying processes.
• the vinyl ester copolymers are converted into the corresponding fluorine-containing polyvinyl alcohols by partial or complete saponification of the vinyl ester units.
• the saponification of the vinyl ester copolymers is preferably effected by alcoholysis.
• This alcoholysis is carried out in the presence of a lower alkanol, preferably an alkanol having 1, 2 or 3 carbon atoms, such as, for example, methanol, ethanol, propanol or isopropanol; methanol is particularly preferred in this respect.
• a lower alkanol preferably an alkanol having 1, 2 or 3 carbon atoms, such as, for example, methanol, ethanol, propanol or isopropanol; methanol is particularly preferred in this respect.
• the alcoholysis is carried out by employing the alkanol in an amount of 10-50%
• the alcoholysis process is carried out in the presence of a basic catalyst.
• the catalyst used can preferably be an alkali metal hydroxide or alkali metal alcoholate.
• suitable catalysts are sodium hydroxide, potassium hydroxide, NH 3 , sodium methylate, ethylate and propylate, and also potassium methylate, ethylate and propylate.
• the basic catalyst is used in the form of a solution, an alkanol of the abovementioned type being employed as the solvent.
• the amount of a solution, for example 10% strength by weight, of the catalyst in an alkanol is usually 0.1-10% by weight, preferably 0.4-3% by weight, relative to the proportion of vinyl ester in the copolymer.
• the concentration of the catalyst in the alcoholic catalyst solution used is advantageously within the range from 5 to 25% by weight, preferably 8 to 20% by weight.
• the vinyl ester copolymer is saponified or alcoholyzed by dissolving it in a lower alkanol at a temperature of 10°-80° C., preferably 20°-60° C. and especially at room temperature.
• Specific amounts of catalyst solution are added to the homogeneous vinyl ester copolymer solution at a temperature of 10°-40° C., preferably 20°-30° C., depending on the degree of hydrolysis to be established, and vigorous stirring or mixing is carried out.
• the transesterification reaction sets in immediately after the alcoholic catalyst solution has been added.
• the time required for the transesterification is 1-130 minutes, preferably 30-90 minutes and especially 40-80 minutes.
• the vinyl alcohol copolymer obtained by the transesterification reaction is neutralized, washed and dried in a customary manner.
• Neutralization is carried out by means of an inorganic, or preferably organic, acid, for example phosphoric acid or acetic acid.
• the fluoroine-containing polyvinyl alcohols according to the invention can be water-soluble or soluble in water to a limited extent, swellable in water or insoluble in water, depending on the content in the polymer of the individual comonomer components.
• the degree of saponification of the saponifiable structural units is within the range from 40 to 100, preferably 60-99 and especially 70-98, mole %.
• the alcoholysis products or saponification products of the vinyl ester copolymers according to the invention i.e. the vinyl alcohol copolymers, which are also according to the invention, can be used as emulsifiers, agents for increasing viscosity or protective colloids or for the preparation of aqueous hydraulic fluids and also as flooding agent additives for tertiary petroleum extraction.
• they are suitable for the preparation of aqueous, high-viscosity vinyl alcohol copolymer solutions, whereas the corresponding starting vinyl ester copolymers can have low reduced specific viscosities in organic solvents, i.e. it is possible to formulate high concentrations of the starting vinyl ester copolymers in the methanolic saponification solutions.
• the vinyl alcohol copolymers make it possible to achieve corresponding viscosities even at low concentrations in solution.
• the known copolymeric polyvinyl acetates which have been modified with effective amounts of tetrafluoroethylene have a high reduced specific viscosity in the solvent ethyl acetate, while the aqueous solutions of their saponification products, depending on the degree of hydrolysis, exhibit in some cases precipitations or a homogeneous solution behavior at viscosities which are merely within the range of the fairly high known solution viscosities of unmodified polyvinyl alcohols.
• the partially hydrolyzed vinyl ester copolymers according to the invention which can constitute terpolymers or quaterpolymers, can be extruded very readily to give films which have substantially smaller surface distortions than films formed from vinyl alcohol polymers which are not modified according to the invention.
• copolymeric polyvinyl alcohols modified according to the invention are also suitable for coating paper.
• the films of the fluorinated copolymeric polyvinyl alcohols according to the invention obtained from an aqueous phase, exhibit a pronounced hydrophobic behavior in comparison with unmodified polyvinyl alcohol and also in comparison with polyvinyl alcohol which has been modified by tetrafluoroethylene units.
• the fluorinated copolymeric polyvinyl alcohols according to the invention possess excellent emulsifying properties.
• Emulsions have been prepared for this purpose, and the appearance or migration of the phase boundary formed when the emulsions are destabilized has been observed, as a function of time, in a closed measuring cylinder.
• the emulsions are prepared in such a way that they have a content of 8% by weight of copolymeric polyvinyl alcohol modified according to the invention in an emulsion containing 50% by weight of nonaqueous constituents. This is effected by dissolving 12 g of the appropriate fluorine-containing copolymeric polyvinyl alcohol in 162 g of H 2 O, and emulsifying 150 g of monomeric vinyl acetate in this solution.
• comparison emulsions are prepared in which the emulsifier or protective colloid used is a conventional, unmodified polyvinyl alcohol having a viscosity of 26 cP and a degree of hydrolysis of 82.6-83 mole %, or a polyvinyl alcohol which contains 4.1% by weight of comonomer units of tetrafluoroethylene and has a viscosity of 40.4 mPa.s and a degree of hydrolysis of 85.9 mole %.
• the emulsifier or protective colloid used is a conventional, unmodified polyvinyl alcohol having a viscosity of 26 cP and a degree of hydrolysis of 82.6-83 mole %, or a polyvinyl alcohol which contains 4.1% by weight of comonomer units of tetrafluoroethylene and has a viscosity of 40.4 mPa.s and a degree of hydrolysis of 85.9 mole %.
• the copolymeric polyvinyl alcohol containing perfluorooctylethylene comonomer units exhibits a markedly improved emulsion stability (over a duration of 50 days), even at low proportions of the said comonomer units.
• This excellent behavior is also found in copolymeric polyvinyl alcohols according to the invention containing perfluorohexylethylene or allyl tetrafluoroethyl ether as the fluorine-containing comonomer.
• the fluorine-containing, copolymeric polyvinyl alcohols according to the invention produce a notably higher emulsion stability and/or exhibit an increase capacity for emulsification, in comparison with known polyvinyl alcohols or known fluorine-containing, copolymeric polyvinyl alcohols.
• the invention also relates to copolymers containing carboxyl groups.
• vinyl esters for example vinyl acetate
• crotonic acid or maleic acid if the resulting copolymers are saponified to give the acid-modified, copolymeric polyvinyl alcohols, polyvinyl alcohols are obtained which have a low viscosity in a 4% strength by weight aqueous solution.
• the viscosity of a 10% strength by weight aqueous solution measured at 85° C. in a Rheomat 30 made by Contraves, is outside the range of 60-120 mPa.s which is desirable for sizes.
• the products are soluble in alkali, which is considered an important requirement for use as sizing agents, the resulting films are brittle.
• a further surprising fact is that, even at low contents of fluorine-containing comonomer according to the invention in the quaterpolymeric polymer, as marked effect can be observed in respect of viscosity.
• the water absorption measured after an operating time of 8 days at 65% and 85% relative humidity, ranges between 5 and 40% by weight, preferably between 8 and 25% by weight.
• the viscosity values of a 10% strength by weight aqueous solution, measured at 85° C. in a Contraves Rheomat 30, can cover a wide range from 5 to 180 mPa.s, preferably 35 to 140 mPa.s and especially 60-120 mPa.s, depending on the proportion of comonomer used.
• fluorine-containing copolymers according to the invention and containing carboxyl groups can be prepared by the (mass) batch process or by the metering process.
• the components employed can preferably be, for example, the following comonomers:
• Vinyl esters for example vinyl formate, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl laurate and vinyl stearate and also vinyl esters of branched carboxylic acids having 10-12 carbon atoms. They can be employed on their own or as a mixture with one another. It is preferable to use vinyl acetate.
• fluorine-containing comonomers those having long-chain perfluoroalkyl radicals are preferred over those having short-chain perfluoroalkyl radicals. This is important, in particular, for the technical properties in use of the copolymeric polyvinyl alcohols prepared from the terpolymers by saponification.
• the fluorinated comonomers employed are, therefore, preferably those containing a perfluorinated alkyl radical having 4-20, preferably 5-15 and especially 6-8, carbon atoms.
• the perfluorinated alkyl radical can also be attached to the ethylenically unsaturated grouping of the compound via an oxygen atom.
• Perfluorohexylethylene and perfluorooctylethylene are particularly preferred fluorine-containing comonomers.
• the acid component originates from the group of unsaturated monocarboxylic and dicarboxylic acids corresponding to the general formula II.
• ⁇ , ⁇ -unsaturated monocarboxylic acids acrylic acid, methacrylic acid, crotonic acid, vinylacetic acid and allylacetoacetic acid.
• Dicarboxylic acids such as, for example, maleic, fumaric, itaconic or citraconic acid, can also be used with advantage.
• organic solvents can also be added to the reaction mixture as a diluent.
• Methanol or ethanol is preferred in this respect, but particularly methanol.
• the preparation of these copolymers according to the invention can be effected by simple free radical polymerization, two mixtures being prepared, one of which is initially taken in the reaction vessel (mixture I), while the other (mixture II) is metered in.
• the mixture initially taken in the reaction vessel (mixture I) is composed, for example, of vinyl acetate and the total amount of an initiator suitable for elevated temperatures.
• the amount of mixture I is about 10% by weight of the total amount of vinyl acetate.
• initiators which are particularly preferred for elevated temperatures of 65°-90° C. are peroxides, such as dibenzoyl peroxide.
• Per-esters such as t.-butyl per-2-ethylhexanoate, are employed in an amount of 0.01-1.0% by weight, preferably 0.1-0.6% by weight, relative to the vinyl ester.
• the mixture II is composed of the remainder of the vinyl acetate and the monomeric carboxylic acid and the monomeric perfluoroalkyl compound.
• Crotonic acid in an amount of 0.5-8% by weight, in particular 1-6% by weight and preferably 1.5-5% by weight, relative to the total mixture excluding initiator, is preferably employed as the carboxylic acid.
• perfluoroalkyl compounds which are particularly preferred are the comonomers perfluorohexylethylene and perfluorooctylethylene. They are present in the total mixture at a concentration of 0.05-10% by weight, preferably 0.1-5% by weight and particularly 0.2-3% by weight.
• Polymerization is carried out by heating the initially taken mixture I to 70°-80° C.
• a start is made with metering in the mixture II.
• Metering in is carried out for 1-6 hours, preferably for 3 hours.
• the polymerization temperature is kept constant during this time.
• dilution is carried out in stages with an organic solvent, such as, for example, methanol.
• additional amounts, preferably 0.1-0.3% by weight, relative to the total concentration of monomers, of initiator, such as, for example, bis-(4-tert.-butylcyclohexyl)peroxodicarbonate or bis-(cyclohexyl)peroxodicarbonate, are added to the reaction mixture in order to increase the conversion.
• initiator such as, for example, bis-(4-tert.-butylcyclohexyl)peroxodicarbonate or bis-(cyclohexyl)peroxodicarbonate
• solutions diluted in this manner can be employed directly for saponification to give the quater-polymer according to the invention.
• the saponification and/or the alcoholysis process are carried out in the presence of a basic catalyst.
• the catalyst preferably used is an alkali metal hydroxide or alkali metal alcoholate.
• suitable saponifying agents are sodium hydroxide, potassium hydroxide, NH 3 , sodium methylate, ethylate, and propylate and potassium methylate, ethylate and propylate.
• the catalyst is employed in the form of a solution, an alkanol of the type mentioned above preferably being used as the solvent.
• the amount of a, for example 10% strength by weight, solution of the catalyst in the alkanol can usually be 0.1-10% by weight, preferably 0.4-3% by weight, relative to the copolymeric polyvinyl ester component.
• the concentration of the catalyst in the alcoholic catalyst solution used is preferably within the range from 5 to 25% by weight, advantageously 8 to 20% by weight.
• the degree of saponification of the saponifiable vinyl ester structural units is within the range from 40 to 100, preferably 60 to 99 and particularly 88 to 98, mole %.
• the yield is 2834 g of copolymer.
• the copolymer obtained has a reduced specific viscosity of 99.7 ml/g, measured on a solution of the copolymer having a concentration c of 1.02 g/100 ml at 25° C. in ethyl acetate.
• the mixture is homogenized by being stirred for approx. 5 minutes.
• the resulting alkaline gel is then ground and, 51 minutes later, neutralized with 6 ml of concentrated acetic acid in 500 g of methanol.
• the product is only partly soluble in water.
• a mixture of 1485 g of vinyl acetate, 15 g of perfluoropropyl vinyl ether, 5 g of dibenzoyl peroxide (75% strength by weight) and 643 g of methanol is charged into a 3 l autoclave equipped with a stirrer. The mixture is heated to 80° C. and is copolymerized for 5 hours at this temperature and under an autogenous pressure of 1.5-1.8 bar.
• the solution is diluted from 70% by weight to 60% by weight by adding methanol. After the solution has been dried, 1395 g of solid copolymer containing 0.97% by weight of perfluoropropyl vinyl ether units are obtained. This last proportion of comonomer was determined via analysis for fluorine.
• Fluorine analysis indicates a content of 1.56% by weight of fluorine-containing comonomer units, relative to the terpolymer.
• the viscosity of a 4% strength by weight aqueous solution of the terpolymer is 4.2 mPa.s.
• a mixture of 3992 g of vinyl acetate, 8 g of perfluorohexylethylene and 13.33 g of dibenzoyl peroxide (75% strength by weight) is initially placed in a reaction apparatus according to Example 1 and is heated to 75° C. and subjected to mass polymerization for 30 minutes. After 30 minutes, the mixture is diluted with methanol to a solids content of 80% by weight. The reaction temperature is kept at 62° C. During the further course of the polymerization the solution is diluted with methanol to 30% strength by weight, and, 5 hours later, the solvent and the volatile constituents are removed by distillation. The yield is 3178 g of copolymer.
• the reduced specific viscosity of the copolymer is 127.4 ml/g at a concentration c of 1.07 g/100 ml, measured in ethyl acetate at 25° C.
• Copolymerization of a mixture of 792 g of vinyl acetate and 8 g of perfluorooctylethylene and 2.66 g of dibenzoyl peroxide is carried out similarly to Example 1, but in a 6 l reaction flask equipped with a reflux condenser, a thermometer and a stirrer.
• the conversion in the reaction is 72.9% by weight, relative to the total amount of monomers employed.
• the resulting copolymer has a reduced specific viscosity of 102.8 ml/g, measured in ethyl acetate at 25° C.
• the saponification temperature is 23° C. After 60 minutes, the resulting gel is granulated in a mill, and the saponification reaction is stopped by adding 5.9 ml of acetic acid in 500 g of methanol.
• the resulting terpolymer has a degree of hydrolysis of 85 mole % and contains 2.07% by weight of perfluorooctylethylene units, as determined by analysis. It is only partly soluble in water and tends to form a gel.
• the reaction takes place with a conversion of 69.2% by weight, relative to the total amount of monomers employed.
• a mixture of 975.1 g of vinyl acetate and 3.27 g of dibenzoyl peroxide is sucked into a 3 l autoclave under a slight vacuum via a gas vessel containing 4.9 g of hexafluoroisobutene.
• the subsequent copolymerization of the mixture is carried out at 70° C. for a polymerization time of 5 hours.
• the batch is diluted with 960 g of methanol.
• the copolymer obtained contains 0.5% by weight of hexafluoroisobutene and has a reduced specific viscosity of 89.2 ml/g, measured in ethyl acetate at 25° C. at a concentration c of 1.01 g/100 ml.
• 16 g of allyl hexafluoropropyl ether are mixed with 784 g of vinyl acetate and 2.66 g of dibenzoyl peroxide and are polymerized in the apparatus described in Example 7 at 40° C. for 5.5 hours. During the polymerization 807 g of methanol are added to the batch.
• a mixture of 3980 g of vinyl acetate, 20 g of perfluorooctylethylene and 0.25% by weight, relative to vinyl acetate, of dibenzoyl peroxide, as initiator, is prepared for polymerization by the metering process in a reaction apparatus corresponding to Example 1, but equipped with a metering device.
• the remaining vinyl acetate is removed by vacuum distillation while further methanol is added.
• the resulting terpolymer has a degree of hydrolysis of 86.3 mole %, and the solution viscosity (Hoppler) of a 4% strength by weight aqueous solution is 754.0 mPa.s.
• the product is homogeneous and forms a clear solution in water.
• the contents of comonomer in the polyvinyl acetate copolymer were determined quantitatively by fluorine analysis.
• the reduced specific viscosity of the resulting polyvinyl acetate is 125.8 ml/g at a concentration c of 1.0 g/100 ml and at a temperature of 25° C. (Ostwald viscometer), measured in ethyl acetate.
• the saponification reaction is terminated by pouring the granulated saponification product into a mixture of 8.4 ml of concentrated acetic acid and 800 g of methanol. The product is then dried at 70° C. in a vacuum cabinet. This gives a polyvinyl alcohol homopolymer having a degree of hydrolysis of 85.7 mole % and a H/o/ ppler viscosity of 14.9 mPa.s.
• a 4% strength by weight aqueous solution of the product is homogeneous and exhibits no turbidity at all.
• the comparison product obtained has a markedly lower viscosity.
• a tetrafluoroethylene/vinyl acetate copolymer having a TFE content of 2.7% by weight are dissolved in 2267 g of methanol.
• the copolymer has a reduced specific viscosity of 359.4 ml/g in ethyl acetate at 25° C. and a concentration c of 1.02 g/100 ml.
• the resulting modified polyvinyl alcohol contains 4.1% by weight of copolymerized tetrafluoroethylene.
• the degree of hydrolysis is 85.9 mole%.
• the H/o/ ppler viscosity of a 4% strength by weight aqueous solution is 40.4 mPa.s, measured at 23° C.
• the aqueous solution is cloudy and has a deposit after standing for a prolonged period.
• the product from Comparison Example C is treated with 1.5% by weight of 10% strength by weight methanolic sodium hydroxide solution at room temperature.
• the methanolysis reaction is terminated after 3 hours by means of equimolar amounts of concentrated acetic acid in 400 g of methanol.
• the resulting TFE-containing, terpolymeric polyvinyl alcohol containing 4.5% by weight of tetrafluoroethylene units has a degree of hydrolysis of 97.4 mole %.
• the H/o/ ppler viscosity of a 4% strength by weight aqueous solution is 68.2 mPa.s, measured at 23° C.
• the aqueous solution is homogeneous and clear and exhibits no phase separation even after standing for a prolonged period.
• the polyvinyl acetate modified by tetrafluoroethylene units has a high reduced specific viscosity in the solvent ethyl acetate, which results in considerable dissolving problems, for example in methanol, and makes the preparation of methanolic solutions of fairly high concentrations considerably more difficult or can even render this impossible.
• the polyvinyl acetates, modified in accordance with the invention, of Examples 14-18 do not have this disadvantage.
• a mixture (mixture II) composed of 687.6 g of mixture I, 32.0 g of crotonic acid and 8.0 g of perfluorohexylethylene is prepared as the solution to be metered in from a 1 l metering funnel.
• Mixture I which was initially taken, is heated to 73° C. When this temperature has been reached, a start is made with metering in mixture II. Mixture II is metered in for 3 hours.
• the polymerization temperature is kept between 73° and 74° C. during this time.
• the bath temperature is kept constant at 80° C. for the entire duration of the polymerization. If the internal temperature exceeds 75° C. about 45-60 minutes after the end of metering in mixture II, the reaction solution is diluted in stages with 89 g, 111 g, 143 g and 190 g of methanol. The reaction temperature falls to 60° C. after the first addition of methanol and rises to 65° C. in the further course of the polymerization.
• the polymerization solution is diluted with a further 667 g of methanol, the polymerization reaction is terminated by adding 50 mg of hydroquinone, and the mixture is cooled to room temperature.
• the resulting 40% strength by weight methanolic solution has a residual monomer content of 1.69% by weight.
• the reduced specific viscosity of the product at 25° C. in ethyl acetate is found to be 81.3 ml/g, at a concentration c in the ethyl acetate solution of 1.05 g/100 ml.
• the mixture is homogenized by stirring for approx. 2 minutes.
• the resulting solid, alkaline gel is ground and, 45 minutes later, neutralized with 62.4 g of acetic acid, with the addition of 700 g of methanol in the course of 1 hour.
• the neutralized product is washed with methanol and then suction-drained on a suction filter, and the solid product is dried in a drying cabinet. This gives 341 g of quaterpolymeric polyvinyl alcohol having a solids content of 97% by weight.
• the degree of hydrolysis is 95 mole %.
• the viscosity of a 4% strength by weight aqueous solution, measured at 23° C. in a H/o/ ppler viscometer, is found to be 21.1 mPa.s.
• the 10% strength by weight aqueous solution has a viscosity of 85.5 mPa.s, measured at 85° C. in a Contraves Rheomat 30.
• the product has an excellent solubility in alkali.
• mixture II 32 g of crotonic acid and 6.4 g of perfluorooctylethylene are added to 690.2 g of mixture I (mixture II).
• the content of crotonic acid units in the terpolymer can be determined titrimetrically to be 4.5% by weight.
• the polyvinyl alcohol modified according to the invention has a degree of hydrolysis of 94.9 mole % and a 4% strength by weight aqueous solution of it has a viscosity of 23.4 mPa.s at 23° C. (Hoppler).
• the 10% strength by weight aqueous solution of the polyvinyl alcohol quaterpolymer has a viscosity of 134.7 mPa.s, measured at 85° C. using a Rheomat 30.
• the methanolic reaction solution which is 40% strength by weight, has a residual monomer content, determined titrimetrically, of 0.3% by weight.
• the reduced specific viscosity ⁇ sp/c of the copolymer measured in ethyl acetate at 25° C. and at a concentration c of 1.0 g/100 ml, is 86.7 ml/g.
• the crotonic acid content of the copolymer is determined titrimetrically to be 3.2% by weight.
• the neutralized product is washed with further methanol and suction-drained on a suction filter and then dried at 70° C. in a vacuum drying cabinet.
• the resulting terpolymer containing crotonic acid has a degree of hydrolysis of 95.3 mole %.
• the viscosity, measured in a H/o/ ppler viscometer, of a 4% strength by weight aqueous solution of the terpolymer at 23° C. is 9.8 mPa.s at a pH of 7.0.
• a 10% strength by weight aqueous solution of the terpolymer has a viscosity of 20.8 mPa.s at 85° C.
• the product is readily soluble in alkali.
• the viscosity range of 60-120 mPa.s (10% strength by weight solution, 85° C.) in water, which is specified and required for a fiber yarn sizing material, is not achieved by the comparison product from Comparison Example F. The latter is therefore not suitable for use as a fiber yarn sizing agent.
• a further surprising fact is that, inspite of the product from Example 22 having a higher crotonic acid content than the product from Comparison Example F, the viscosity in water of the hydrolysis product, according to the invention, from Example 22 is markedly higher, although a higher crotonic acid content during the polymerization under conditions not in accordance with the invention would have been expected to reduce the viscosity in water of the corresponding polyvinyl alcohols.

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• 1984
  • 1984-04-28 DE DE19843415975 patent/DE3415975A1/de not_active Withdrawn
• 1985
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